The Himalayan glaciers are receding at an increased rate over the last few decades but it is "inconclusive" that global warming is the causative factor behind it, the government said today.

Environment Minister Anil Madhav Dave, in a written reply in the Lok Sabha, said the glaciers in the Himalayas have been by and large shrinking in volume and showing a retreating front.

"Research has shown that Himalayan glaciers have been receding since the end of the Little Ice Age but the recession has increased its rate during the past few decades," he said.

Pointing out that receding of glaciers are rather "irregular" in rate, amount and time of occurrence, Dave said, "There could be several reasons for enhanced rate of glacier melting. One of them is decreasing trend of winter precipitation. However, there is no conclusive evidence for an abnormal annual retreat."

"Evidence for global warming being the causative factor for retreat of glaciers is inconclusive," he said.

The Environment Ministry in collaboration with Indian Space Research Organisation (ISRO) has carried out mapping of Himalayan glaciers using Indian satellite data during 2004-07, the Union minister said.

"The study shows that there are 34,919 glaciers spread over 75,779 square kilometres in Indus, Ganga and Brahmaputra basins covering the Himalaya and Trans-Himalaya including Karakoram region," Dave said.

ISRO has monitored the advance and retreat of 2,018 glaciers across the Himalayan region using satellite data from 2000-01 to 2010-11, he said.

"The study shows that 87 per cent of glaciers showed no change, 12 per cent glaciers retreated and one per cent glaciers have advanced," he said.

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